Effects of altering palmitylation sites on biosynthesis and function of the influenza virus hemagglutinin

Naim, Hussein Y.; Amarneh, Bilal; Ktistakis, Nicholas T.; Roth, Michael G.

doi:10.1128/jvi.66.12.7585-7588.1992

Cited by 55 publications

(39 citation statements)

References 22 publications

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“…Whether this effect was due to acylation being prevented is unclear but it is conceivable that the membrane-inserted hydrophobic acyl chains play a role in fusion pore formation. A positive role of palmitoylation in cell fusion has been reported for influenza virus HA protein (Naeve and Williams, 1990;Sakai et al, 2002), but this role was found to be negative for VSV (Whitt and Rose, 1991), influenza virus (Naim et al, 1992;Steinhauer et al, 1991), or the Murine leukemia virus fusion protein (Yang and Compans, 1996).…”

Section: Discussionmentioning

confidence: 97%

Spike protein assembly into the coronavirion: exploring the limits of its sequence requirements

et al. 2005

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The coronavirus spike (S) protein, required for receptor binding and membrane fusion, is incorporated into the assembling virion by interactions with the viral membrane (M) protein. Earlier we showed that the ectodomain of the S protein is not involved in this process. Here we further defined the requirements of the S protein for virion incorporation. We show that the cytoplasmic domain, not the transmembrane domain, determines the association with the M protein and suffices to effect the incorporation into viral particles of chimeric spikes as well as of foreign viral glycoproteins. The essential sequence was mapped to the membrane-proximal region of the cytoplasmic domain, which is also known to be of critical importance for the fusion function of the S protein. Consistently, only short C-terminal truncations of the S protein were tolerated when introduced into the virus by targeted recombination. The important role of the about 38-residues cytoplasmic domain in the assembly of and membrane fusion by this approximately 1300 amino acids long protein is discussed.

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Section: Discussionmentioning

confidence: 97%

Spike protein assembly into the coronavirion: exploring the limits of its sequence requirements

et al. 2005

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“…All of the cysteine residues in the spike that potentially could be acylated are in the cys domain, suggesting that mutations to this region may be inhibiting fusion by interfering with palmitylation of the spike protein. Since palmitylation is known to affect a variety of processes mediated by or involving fusion proteins, including infection of cells, membrane fusion, and virus assembly (Glick and Rothman, 1987;Jin et al, 1996;Melikyan et al, 1997b;Naim et al, 1992;Schroth-Diez et al, 1998;Zurcher et al, 1994), studies are in progress to identify the sites of acylation and determine the role that palmitylation may play in spike protein function.…”

Section: Discussionmentioning

confidence: 99%

Coronavirus-Induced Membrane Fusion Requires the Cysteine-Rich Domain in the Spike Protein

2000

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The spike glycoprotein of mouse hepatitis virus strain A59 mediates the early events leading to infection of cells, including fusion of the viral and cellular membranes. The spike is a type I membrane glycoprotein that possesses a conserved transmembrane anchor and an unusual cysteine-rich (cys) domain that bridges the putative junction of the anchor and the cytoplasmic tail. In this study, we examined the role of these carboxyl-terminal domains in spike-mediated membrane fusion. We show that the cytoplasmic tail is not required for fusion but has the capacity to enhance membrane fusion activity. Chimeric spike protein mutants containing substitutions of the entire transmembrane anchor and cys domain with the herpes simplex virus type 1 glycoprotein D (gD-1) anchor demonstrated that fusion activity requires the presence of the A59 membrane-spanning domain and the portion of the cys domain that lies upstream of the cytoplasmic tail. The cys domain is a required element since its deletion from the wild-type spike protein abrogates fusion activity. However, addition of the cys domain to fusion-defective chimeric proteins was unable to restore fusion activity. Thus, the cys domain is necessary but is not sufficient to complement the gD-1 anchor and allow for membrane fusion. Site-specific mutations of conserved cysteine residues in the cys domain markedly reduce membrane fusion, which further supports the conclusion that this region is crucial for spike function. The results indicate that the carboxyl-terminus of the spike transmembrane anchor contains at least two distinct domains, both of which are necessary for full membrane fusion.

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“…The carboxyl terminal cysteine residues of viral membrane glycoproteins have been reported to serve as potential palmitoylation sites (Ponimaskin and Schmidt, 1995;Rose et al, 1984;Schlesinger et al, 1993;Schmidt, 1989;Sefton and Buss, 1987). Palmitoylation of viral glycoproteins involved in cell fusion have been shown to affect the ability to fuse cellular membranes, virus infection of cells, and virus assembly (Glick and Rothman, 1987;Jin et al, 1996;Melikyan et al, 2000;Naim et al, 1992;Schroth-Diez et al, 1998;Zurcher et al, 1994). Specifically for coronaviruses, it has been shown that the S2 fragment of the MHV and the human coronavirus A59 S glycoprotein is palmitoylated on its carboxyl-terminal region (Niemann and Klenk, 1981;Sturman et al, 1980;van Berlo et al, 1987).…”

Section: S-palmitoylation and S-mediated Cell Fusionmentioning

confidence: 99%

Palmitoylation of the cysteine-rich endodomain of the SARS–coronavirus spike glycoprotein is important for spike-mediated cell fusion

et al. 2007

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The SARS-coronavirus (SARS-CoV) is the etiological agent of the severe acute respiratory syndrome (SARS). The SARS-CoV spike (S) glycoprotein mediates membrane fusion events during virus entry and virus-induced cell-to-cell fusion. The cytoplasmic portion of the S glycoprotein contains four cysteine-rich amino acid clusters. Individual cysteine clusters were altered via cysteine-to-alanine amino acid replacement and the modified S glycoproteins were tested for their transport to cell-surfaces and ability to cause cell fusion in transient transfection assays. Mutagenesis of the cysteine cluster I, located immediately proximal to the predicted transmembrane, domain did not appreciably reduce cell-surface expression, although S-mediated cell fusion was reduced by more than 50% in comparison to the wild-type S. Similarly, mutagenesis of the cysteine cluster II located adjacent to cluster I reduced S-mediated cell fusion by more than 60% compared to the wild-type S, while cell-surface expression was reduced by less than 20%. Mutagenesis of cysteine clusters III and IV did not appreciably affect S cell-surface expression or S-mediated cell fusion. The wild-type S was palmitoylated as evidenced by the efficient incorporation of (3)H-palmitic acid in wild-type S molecules. S glycoprotein palmitoylation was significantly reduced for mutant glycoproteins having cluster I and II cysteine changes, but was largely unaffected for cysteine cluster III and IV mutants. These results show that the S cytoplasmic domain is palmitoylated and that palmitoylation of the membrane proximal cysteine clusters I and II may be important for S-mediated cell fusion.

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Effects of altering palmitylation sites on biosynthesis and function of the influenza virus hemagglutinin

Cited by 55 publications

References 22 publications

Spike protein assembly into the coronavirion: exploring the limits of its sequence requirements

Spike protein assembly into the coronavirion: exploring the limits of its sequence requirements

Coronavirus-Induced Membrane Fusion Requires the Cysteine-Rich Domain in the Spike Protein

Palmitoylation of the cysteine-rich endodomain of the SARS–coronavirus spike glycoprotein is important for spike-mediated cell fusion

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